Pressure transmitters such as the Rosemount 3051 series are used in protecting gas turbines and other rotating machinery. The pressure transmitters have multiple uses including: monitoring differential pressure across filters and strainers to prevent plugged filters from going undetected, thereby protecting the rotating equipment from debris and maintaining efficiency; measuring and maintaining lube oil pressure for preventing damage or failure of critical assets such as pumps, compressors, conveyors and other rotating assets; measuring and monitoring emissions flow to facilitate compliance with government regulations and automated reporting; and providing tank overspill protection.
Pressure transmitters may include several major components—the sensor assembly which includes an LCD display screen for displaying measured and monitored parameters, the manifold on which the sensor assembly sits, at least two opposed drain/vent valves which are threaded into the transmitter base and used in the calibration process, and two pressurization valves located on the manifold and also used in the calibration process. The input from a sensor to be monitored by the pressure transmitter is input to the connection port at the top of the sensor assembly.
As shown in FIG. 1, prior art pressure transmitters 12 mounted on a panel 10 have drain/vent valves 14 which oppose the drain/vent valves of adjacent pressure transmitters. The drain/vent valves 14 are oriented 90° from the face of the transmitter base 22. FIG. 2 shows that in conventional pressure transmitters the drain/vent valves 14 are threaded into the side of transmitter base 22 in opposite directions. Also shown in FIG. 1 are, respectively, high (H) and low (L) pressure lines led from independent pressure fluid source (not shown).
Drain/vent valves for pressure transmitters are well known in the prior art, and as used in the exemplary implementations described herein can be of any type and manufacture. One such drain/vent valve is disclosed in International Publication Number WO 98/09146. As noted above, the pressure transmitters described in the exemplary implementations herein described are the Rosemount 3051 series pressure transmitters, but as those skilled in the art would readily recognize other types and manufactures of pressure transmitters can also be used.
It is desirable to mount pressure transmitters arranged in an array on a panel for a bank of machinery such as, for example, gas turbines. Typically a panel can include ten or more pressure transmitters. Each pressure transmitter is typically oriented on the panel so that the High and Low manifold valves 16, 18 are facing to the front of the panel. However, as shown in FIGS. 1 and 2, the drain/vent valves 14 of the pressure transmitters 12 are threaded into the transmitter base 22 so that they are disposed at approximately a 90° angle. Accordingly, adjacent pressure transmitters 12 have drain/vent valves substantially facing each other. With this orientation, a rather large panel is required for mounting the pressure transmitters so that calibration tools, including connectors, meters, etc., can access the drain/vent valves. Even in large sized panels a pressure transmitter cannot be adjusted and/or calibrated without having to temporarily remove the adjacent transmitters from the panel. Space restrictions at the panel location can lead to less than ideal conditions for adjusting each transmitter, resulting in increased time and labor costs.
FIG. 6 shows a schematic representation of conventional pressure transmitters 12 arranged on a panel 60. Each pressure transmitter includes a high pressure valve 16 and a low pressure valve 18 which are used to calibrate the high pressure and low pressure sides of each pressure transmitter serially or one at a time. Of course, as noted above adjacent pressure transmitters must be removed and then reinstalled to the panel to complete the process of calibrating each pressure transmitter.
More particularly, for calibrating the first pressure transmitter 12(1A), low and high pressure valve 18 and 16 must first be closed. Then, the drain/vent valves (also called stinger ports) are removed from both sides of transmitter base 22. Thereafter field calibration/verification check equipment is connected to the low pressure side of transmitter 12(1A). At this point low pressure side calibration is performed. For the high pressure side the field calibration/verification check equipment is moved from the low pressure side to the high pressure side. Once connected to the high pressure side the calibration is performed. The calibration is performed by applying high and low pressure fluid through respective high 66 and low 68 pressure lines to the transmitter. After calibration, the calibration/verification check equipment is removed from the stinger ports and the drain/vent valves are reinstalled. Finally, the low and high manifold valves 16, 18 on transmitter base 22 are opened. This same sequence of steps is repeated for each of the pressure transmitters 12(1B) through 12(1N). This serial pressure calibration process is very time consuming and labor intensive, and must also be performed in conjunction with the calibration process performed through the drain/vent valves which requires removal of adjacent pressure transmitters.